When choosing a mate, lots of animals are choosy; females look for desirable traits exhibited by males, and males often compete for females. Although it surprises many people, plants do the same thing, it's just harder to document. In seed plants, pollen grains are tiny males that disperse to find females, and they may have to compete to acquire a mate. In flowering plants pollen landing on a stigma must race to get to the females by growing pollen tubes to the ovules across a distance equivalent to a marathon in comparison to their size. In this way certain genotypes have an advantage, and it's been shown that these will make larger, more vigorous offspring. And it's not just the males because the floral tissue and the females within may exert influences that make certain genotypes successful or unsuccessful at mating. This and many other studies have found diverse ways in which plants select among available genotypes, choices that involve no thought obviously, but choices nonetheless, for producing their offspring (embryo within seeds). Here's a nice article about several recent studies to give you a new or greater appreciation of what goes on with flowers and pollination.